• The WhatsApp web QR code will not load if your browser does not support media. If you've turned off media, turn it back on. If you haven't already done so, the simplest solution is to restore your browser's default settings. This will most likely fix any other issues you're having with your browser.
• Some free public Wi-Fi networks, such as those found at airports, charge customers a fee to access their internet for the purpose of using messaging apps. This would also make it impossible for the WhatsApp website to load properly.
• Go to Camera, then Settings. Make sure that Scan QR Codes is turned on. Check your Camera settings to see if it's turned on.

Read More: How can I use WhatsApp using my phone number on my laptop and without scanning the QR code?